.NET (Core and Framework)

Happy Day,

       I am Working on a Project FrontEnd(Asp.net) Coding C# ANd Back End(Sql Server 2008).... I have included sending mail concept to users(i.e If the request to send the Password To mail) in my Project... Now I am Planning to include the <big>Message Sending Concept</big> for the users(i.e If the request to send the Password To their mobile)... So is their Any way that i can send message to their mobile...
One Way I heard is Sending Using Free Sms Api's...
So can i know any <big>Free(Working) Sms API's</big> Which Allows me to send message using Any Providers such as(Way2sms,Fullonsms,160by2 etc...)...
Or is their any other way that i can send the Message for free....

Thanks In Advance....
Happy Coding....

public static bool SetCurrentUser(String UserKey, String Password)
{
    SqlConnection myConnection = new SqlConnection("server=localhost;"+
                               "Trusted_Connection=yes;" +
                               "database=SgTextiles; " +
                               "connection timeout=30");
     myConnection.Open();

    SqlCommand myCommand = new SqlCommand("SELECT *FROM dbo.Users where UserKey=" +
    UserKey + "AND Password=" + Password, myConnection);
    SqlDataReader myReader = myCommand.ExecuteReader();
    if (myReader.Read())
    {
        CurrentUserName = myReader["UserName"].ToString();
        CurrentUserKey = myReader["UserKey"].ToString();
        String UID= myReader["ID"].ToString();
        CurrentUserID=UID.??????;
        CurrentRole = 0;




    }
    else
    {
        return false;
    }



    return true;

}